Growth hormone is a major participant in the control of several complex physiologic processes including growth and metabolism. Growth hormone is known to have a number of effects on metabolic processes such as stimulating protein synthesis and mobilizing free fatty acids, and causing a switch in energy metabolism from carbohydrate to fatty acid metabolism. Deficiencies in growth hormone can result in dwarfism and other severe medical disorders.
The release of growth hormone from the pituitary gland is controlled directly and indirectly by a number of hormones and neurotransmitters. Growth hormone release can be stimulated by growth hormone releasing hormone (GHRH) and inhibited by somatostatin.
The use of certain compounds to increase levels of growth hormone in mammals has previously been proposed. Anamorelin is one such compound. Anamorelin is a synthetic orally active compound originally synthesized in the 1990s as a growth hormone secretagogue for the treatment of cancer related cachexia. The free base of anamorelin is chemically defined as:                (3R) 1-(2-methylalanyl-D-tryptophyl)-3-(phenylmethyl)-3-piperidinecarboxylic acid 1,2,2trimethylhydrazide,        3-{(2R)-3-{(3R)-3-benzyl-3-[(trimethylhydrazino)carbonyl]piperidin-1-yl}-2-[(2-met hylalanyl)amino]-3-oxopropyl}-1H-indole, or        2-Amino-N-[(1R)-2-[(3R)-3-benzyl-3-(N,N′,N′-trimethylhydrazino-carbonyl)piperidin-1-yl]-1-(1H-indol-3-ylmethyl)-2-oxoethyl]-2-methylpropionamideand has the below chemical structure:        

U.S. Pat. No. 6,576,648 to Ankerson reports a process of preparing anamorelin as the fumarate salt, with the hydrochloride salt produced as an intermediate in Step (j) of Example 1. U.S. Pat. No. 7,825,138 to Lorimer describes a process for preparing crystal forms of the free base of anamorelin.
There is a need to develop anamorelin monohydrochloride as an active pharmaceutical ingredient with reduced impurities and improved stability over prior art forms of anamorelin hydrochloride, such as those described in U.S. Pat. No. 6,576,648, having good solubility, bioavailability and processability. There is also a need to develop methods of producing pharmaceutically acceptable forms of anamorelin monohydrochloride that have improved yield over prior art processes, reduced residual solvents, and controlled distribution of chloride content.